From fffd213c8cba2135afda493d797c41c10354770e Mon Sep 17 00:00:00 2001
From: Othmar Gsenger <otti@anytun.org>
Date: Sat, 12 Apr 2008 11:38:42 +0000
Subject: big svn cleanup

---
 src/authAlgo.cpp | 125 +++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 125 insertions(+)
 create mode 100644 src/authAlgo.cpp

(limited to 'src/authAlgo.cpp')

diff --git a/src/authAlgo.cpp b/src/authAlgo.cpp
new file mode 100644
index 0000000..6b1c9ec
--- /dev/null
+++ b/src/authAlgo.cpp
@@ -0,0 +1,125 @@
+/*
+ *  anytun
+ *
+ *  The secure anycast tunneling protocol (satp) defines a protocol used
+ *  for communication between any combination of unicast and anycast
+ *  tunnel endpoints.  It has less protocol overhead than IPSec in Tunnel
+ *  mode and allows tunneling of every ETHER TYPE protocol (e.g.
+ *  ethernet, ip, arp ...). satp directly includes cryptography and
+ *  message authentication based on the methodes used by SRTP.  It is
+ *  intended to deliver a generic, scaleable and secure solution for
+ *  tunneling and relaying of packets of any protocol.
+ *
+ *
+ *  Copyright (C) 2007 anytun.org <satp@wirdorange.org>
+ *
+ *  This program is free software; you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License version 2
+ *  as published by the Free Software Foundation.
+ *
+ *  This program is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License
+ *  along with this program (see the file COPYING included with this
+ *  distribution); if not, write to the Free Software Foundation, Inc.,
+ *  59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+ */
+
+#include "authAlgo.h"
+#include "log.h"
+#include "buffer.h"
+#include "encryptedPacket.h"
+
+#include <iostream>
+
+#include <gcrypt.h>
+
+//****** NullAuthAlgo ******
+void NullAuthAlgo::generate(EncryptedPacket& packet)
+{
+}
+
+bool NullAuthAlgo::checkTag(EncryptedPacket& packet)
+{
+  return true;
+}
+
+u_int32_t NullAuthAlgo::getMaxLength()
+{
+  return MAX_LENGTH_;
+}
+
+//****** Sha1AuthAlgo ******
+
+Sha1AuthAlgo::Sha1AuthAlgo() : ctx_(NULL)
+{
+  gcry_error_t err = gcry_md_open( &ctx_, GCRY_MD_SHA1, GCRY_MD_FLAG_HMAC );
+  if( err )
+    cLog.msg(Log::PRIO_CRIT) << "Sha1AuthAlgo::Sha1AuthAlgo: Failed to open message digest algo";
+}
+
+Sha1AuthAlgo::~Sha1AuthAlgo()
+{
+  if(ctx_)
+    gcry_md_close( ctx_ );
+}
+
+void Sha1AuthAlgo::setKey(Buffer& key)
+{
+  if(!ctx_)
+    return;
+
+  gcry_error_t err = gcry_md_setkey( ctx_, key.getBuf(), key.getLength() );
+  if( err )
+    cLog.msg(Log::PRIO_ERR) << "Sha1AuthAlgo::setKey: Failed to set cipher key: " << gpg_strerror( err );
+}
+
+void Sha1AuthAlgo::generate(EncryptedPacket& packet)
+{
+  if(!packet.getAuthTagLength())
+    return;
+
+  gcry_md_reset( ctx_ );
+
+  gcry_md_write( ctx_, packet.getAuthenticatedPortion(), packet.getAuthenticatedPortionLength() );
+  gcry_md_final( ctx_ );
+
+  u_int8_t* tag = packet.getAuthTag();
+  if(packet.getAuthTagLength() > MAX_LENGTH_)
+    std::memset(tag, 0, (packet.getAuthTagLength() - MAX_LENGTH_));
+  
+  u_int8_t* hmac = gcry_md_read(ctx_, 0);
+  u_int32_t length = (packet.getAuthTagLength() < MAX_LENGTH_) ? packet.getAuthTagLength() : MAX_LENGTH_;
+  std::memcpy(&tag[packet.getAuthTagLength() - length], &hmac[MAX_LENGTH_ - length], length);
+}
+
+bool Sha1AuthAlgo::checkTag(EncryptedPacket& packet)
+{
+  if(!packet.getAuthTagLength())
+    return true;
+
+  gcry_md_reset( ctx_ );
+
+  gcry_md_write( ctx_, packet.getAuthenticatedPortion(), packet.getAuthenticatedPortionLength() );
+  gcry_md_final( ctx_ );
+
+  u_int8_t* tag = packet.getAuthTag();
+  if(packet.getAuthTagLength() > MAX_LENGTH_)
+    for(u_int32_t i=0; i < (packet.getAuthTagLength() - MAX_LENGTH_); ++i)
+      if(tag[i]) return false; 
+  
+  u_int8_t* hmac = gcry_md_read(ctx_, 0);
+  u_int32_t length = (packet.getAuthTagLength() < MAX_LENGTH_) ? packet.getAuthTagLength() : MAX_LENGTH_;
+  if(std::memcmp(&tag[packet.getAuthTagLength() - length], &hmac[MAX_LENGTH_ - length], length))
+    return false;
+
+  return true;
+}
+
+u_int32_t Sha1AuthAlgo::getMaxLength()
+{
+  return MAX_LENGTH_;
+}
-- 
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